While battery advances are great, powering a device from the human body is the next level – and it's here.

Scientists at the University of California San Diego have managed to create a sensors that attaches to human skin and harnesses sweat for power.

The device looks like a temporary tattoo and converts sweat to electricity. Its primary function is to measure lactate, the substance found in sweat, in athletes and patients. This enzyme device collects electrons from the lactate to measure it while at the same time producing current. This is also a great alternative to current invasive blood sample testing. But it's been adapted to do so much more.

The researchers involved in this project turned the results into a bio-battery using the collected electrons. It's not producing a great amount of power yet at 70 microWatts per square centimeter of skin. But the researchers are working on a way to boost the system so it will be powerful enough to charge small gadgets like smartwatches and heart rate sensors.

So in the near future you might be able to go for a run without the worry of losing charge on your device for music and directions. Presuming you're breaking enough of a sweat to keep the gadgets charged.

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